When both attractive and repulsive interactions are present, the systems of classical particles demonstrate a liquid-gas First Order Phase Transition (FOPT), see, e.g., Ref.  [1]}. This transition ends with a critical point (CP)
at temperature
\(T=T_c\) 
where different thermodynamic quantities show abnormal behaviour specific for a second order phase transition.
A concept of the critical exponents
splits a great diversity of the CP phenomena
into several universality classes with the same critical exponents (see, e.g., Ref. [2]}).
